Posted on 05/27/2002 4:26:09 PM PDT by petuniasevan
Faulty Genes Explain Why Cloning Is So Difficult
Mon May 27, 3:07 PM ET
WASHINGTON (Reuters) - Cloning may not always completely reprogram an egg cell the way sexual reproduction does, which would explain why the process fails so often, researchers reported on Monday.
While lawmakers around the world debate whether people should be cloned, animal breeders are busy cloning prize cattle, pigs and a range of other animals, including a cat.
But the process fails more often than it works, and animals often die at or near the time of birth. It has not been entirely clear what goes wrong, but experts say technique seems to be very important.
A team at the University of Connecticut reports another possible explanation -- genes on the X chromosome often express, or turn on, improperly, at least in cloned cattle.
Writing in the journal Nature Genetics, they said they looked at the expression patterns of 10 genes on the X chromosomes in four cloned cows that were born alive and four that died of respiratory distress soon after they died.
They were all made by the same method -- somatic cell nuclear transfer, which involves taking the nucleus out of an egg cell and replacing it with the nucleus of an adult cell.
If done right, this starts the egg growing and dividing as if it had been fertilized by a sperm.
The four heifers that lived were made using cumulus cells, cells that nurture the eggs in the ovaries. Other researchers have reported unusual success using these cells.
The four that died were made using skin cells.
Looking at which genes were turned on and off, which affects the kind of tissue a particular cell will form, the researchers found abnormal patterns in major organs such as the heart, liver, brain, kidney and spleen of all the dead clones.
Live clones appeared to have normal gene expressions in their blood and skin tissues. Organs were not sampled in the healthy animals.
"Our study demonstrates that in clones, even though they can develop to full term, many abnormalities in gene expression exist which may be partially responsible for the developmental abnormalities frequently observed, including death," Dr. Xiangzhong Yang, who led the study, said in a statement.
They also think they explained why many cloned animals have abnormal placentas -- which affects their size and survival.
Normally, only the mother's X chromosome is active in the placenta, while the X chromosome inherited from the father is switched off. But both versions were activated in the dead clones.
"This finding may help to explain the commonly observed abnormal placental problems for cloned animals," Yang said.
Human-cloning proponents, beware.
It's an experiment - remember what that word means!
There are always failures in the beginning of a new experimental procedure (and you learn a lot more from failures than successes).
Don't worry, we'll get the bugs worked out and clone all the best people (that can pay for it).
"Unfortunately, the debate is not over. The Senate will never be able to approve the use of that Clone Army before the Islamists separatists attack."
"This is a crisis! If the Senate votes the Chancellor emergency powers, he could approve the use of the Clone Army in a minute." I also see the "War Creation" Act is still being stalled in the Senate:
As Congress Stalls, States Pursue Cloning Debate Sun May 26, 3:04 PM ET By SHERYL GAY STOLBERG The New York Times WASHINGTON, May 25 After nearly a year of emotional arguments in Congress but no new federal laws the national debate over the future of human cloning has shifted to the states. Six states have already banned cloning in one form or another, and this year alone 38 anticloning measures were introduced in 22 states.
---Perhaps a Resolution to authorize Emergency Powers is in order.
So far. We'll get better at it.
...man wants to play God.
You say that like it's a bad thing!
My prediction is that they will seem to have success, maybe even clone a couple of people, much to the delight of even some here on FR. We'll hear about how ignorant we are because we don't agree with such an act and how we just need to get with the program. But in the end it will come back to haunt the scientists who created it, in the end it will fail because man is not God. God is God, and only He has the power that they are trying to simulate.
Flame away
I'm afraid there is little chance the Senate will act on cloning... I have the Senate tied down in procedure. The anti cloners only other choice would be to submit a plea to the courts. The anti cloners lack of vision will be there undoing... wipe them out all of them
David
I agree with you. No good will come of this - probably lots of suffering IMHO.
"It is a matter of procedures,but I feel confident we can overcome it. The longer we wait, the stronger Bin Laden's armies become. We cannot wait for the Senate to make up its mind about granting the Chancellor-GeorgeW. emergency powers, in order to be able to use that clone army... We have the authority to go now. We must go now...."
Exactly how I feel about current problems with cloning.
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